$ { \left[\begin{array}{rr}{0} & {-1} \\ {2} & {0}\end{array}\right]+\left[\begin{array}{rr}{2} & {-1} \\ {-2} & {2}\end{array}\right] = {?} } $
To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rr}{0}+{2} & {-1}+{-1} \\ {2}+{-2} & {0}+{2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{2} & {-2} \\ {0} & {2}\end{array}\right]}$